Wildfires are becoming an increasing threat to homes and communities across the country, especially in Wildland Urban Interface (WUI) areas. One of the most vulnerable parts of a building during a wildfire is the exterior eaves, the overhanging edge of a roof that often includes soffits, vents, or projections. If embers or flames penetrate these areas, they can quickly ignite the building’s interior, leading to devastating losses.
ASTM E2957 is a rigorous fire test method designed specifically to evaluate the ability of eaves, soffits, and other projections to resist wildfire exposure and prevent flame penetration. It simulates real wildfire conditions, including ember attack and direct flame impingement, providing meaningful data on how well a product performs under extreme threat.
For this test, 1/2-inch oriented strand board (OSB) is often used as the substrate and that’s no coincidence. OSB is one of the most widely used yet highly flammable wood products in construction. It’s an engineered wood product made from strands, adhesives and resin content that make it particularly susceptible to ignition and flame spread, which raises the bar significantly for any protective system tested over it.
Firefree Class A: Surface-Applied Application
Firefree Class A, applied at just 20 mils dry film thickness over 1/2-inch OSB, is the only intumescent coating that has successfully passed ASTM E2957 testing. This is a major achievement, setting Firefree Class A apart from other fire protection products on the market.
How does it work?
The coating expands (intumescent) when exposed to flame or extremely high heat 350°F. During this process the coating will produce a soft char, which insulates the surface preventing flashover, smoke reduction, heat transfer and flame penetration. This allows the eaves, soffits, and other projections to withstand wildfire exposure, helping to prevent embers or flames from breaching the building envelope.
Why This Matters?
- Wildfire defense at critical points: Eaves and soffits are often overlooked but are key pathways for wildfire entry.
- Tested on the worst-case substrate: Passing over OSB proves the system’s performance under the most flammable conditions.
- Leading-edge innovation: Firefree Class A delivers a lightweight, easy-to-apply, and code-aligned solution for wildfire compliance.
Can I leave Firefree Class A Exposed to the Weather?
No. After the 20 mils dry / 30 mils wet application, Firefree Class A must be protected with our proprietary Firefree Exterior (FFE) protective acrylic. The FFE has been tested to ASTM D2898, Method B, for weatherization standards.
As communities strengthen their defenses against wildfires, it’s critical to rely on tested, proven, and effective solutions. Firefree Class A’s success in ASTM E2957 testing makes it a standout choice for developers/builders, building owners, and architects who want to ensure the highest level of protection at one of the building’s most vulnerable points. When it comes to wildfire protection, don’t leave your eaves unprotected — choose a solution that’s accredited third-party tested, certified, and proven.